Rock drill



' E. G. GARTIN I ROCK DRILL Oct. 13, 1936.

Filed Nov. 15, 1935 a. l i Z Q Patented Oct. 13, 1936 UNITED STATES PATENT OFFICE ROCK DRILL Massachusetts Application November 15, 1935, Serial No. 49,989

11 Claims.

This invention relates to rock drills, and more particularly to improvements in a hole blowing means for a hammer rock drill of the pressure fluid actuated type.

5 An object of this invention is to provide an improved rock drill hole blowing means. Another object is to provide in a rock drill of the pressure fluid actuated hammer piston type, improved hole blowing means associated with the fluid distributing valve mechanism and hammer piston. Still another object is to provide an improved hole blowing means for effecting a hole blowing function, embodying means for supplying pressure fluid to a pressure area on the fluid distributing valve and the opposite pressure areas on the hammer piston for holding the distributing valve stationary and tobalance the hammer piston in substantially exhaust closing position within its cylinder so that a hole blowing function is 20 effected in an improved manner. A still further object is to provide an improved rock drill wherein a tappet or striking block is employed for transmitting the. impact blows of the hammer piston to the drill steel, and having improved passage means in the tappet and steel chuck whereby the flow of hole blowing pressure is conducted to the drll steel bore in an improved manner. Yet another object is to provide an improved rock drill hole blowing means controlled by the throttle valve of .the drill hammer motor. These and other objects will, however, hereinafter more fully appear. In the accompanying drawing there is shown for purposes of illustration one form which the invention may assume in practice.

In this drawing, Fig. 1 is a view in longitudinal section through a hammer rock drill in which the illustrative form of the improved hole blowing means is embodied. Fig. 2 is a fragmentary .sectional view taken in the plane of Fig. 1, showingthe moving parts in a different position. V

Fig. 3 is a cross sectional view taken online 3-3 of Fig. 1.

Fig. 4 is a cross sectional view taken on line 4-4- of Fig. 1. Fig. 5 is a side elevational view of the tappet. In this illustrative construction there is shown a hammer rock drill of the pressure fluid actuated type comprising a cylinder I having a bore 2 containing a reciprocable hammer piston 3. The hammer piston has a piston head fitting the cylinder bore and a forwardly projecting striking bar 5 of reduced diameter guided in a bore 6 formed in a front buffer ring I, The rearward portion of the cylinder is formed with an enlarged bore 8 alined with the cylinder bore 2, and. arranged in the bore 8 is a cylindrical rear head 9 and a head member ill, the latter abutting the head 9 and cooperating therewith to form a valve chest. Also arranged in the bore 8 and abutting the member I is a ratchet ring I I, and a rear plate l2. The parts 9, III, II and I2 are held in position within the bore 8 by a rear head block [3 suitably attached to the rear end of the cylinder. The buffer ring I is secured within the forward end of the cylinder bore by a front chuck housing I4 suitably attached to the front end of the cylinder, and rotatably mounted in the chuck housing is a chuck sleeve l carrying a chuck bushing I6 in which is mounted the shank i! of a usual hollow rock drill steel. Arranged within the ratchet ring H is a pawl carrier N3 of a conventional design, carrying pawls engaging the teeth of the ratchet ring and having a forwardly projecting rifle bar l9 formed with spiral grooves connected to spiral lugs of a usual rifle nut secured within the rear end. of the hammer piston. The piston striking bar 5 is formed with straight longitudinal grooves 2| engageable with straight lugs formed on a chuck nut 22 secured within the rotatable chuck sleeve I5. As the hammer piston 3 reciprocates within the cylinder bore, it is rotated by the rifle bar IQ of the ratchet and pawl mechanism in a well known manner and the rotative movement of the hammer piston is transmitted through the straight grooves on the piston striking bar and the chuck sleeve to the drill steel. Guided for reciprocatory movement in the chuck sleeve is a tappet or striking block- 23 having an enlarged head fitting the chuck sleeve bore 24 and a reduced body portion fitting the reduced chuck sleeve bore 25. This tappet is adapted to transmit the impact blows of the hammer piston to the drill steel shank. The drill steel is formed with a central longitudinal bore 26 extending therethrough for conducting cleansing fluid to the cutting end of the drill steel to blow out the cuttings from the drill hole. Secured within the rear head block I3 is a gland plug 2'! through which cleansing liquid is conducted to a tube 28 extending centrally through axial bores in the rifle bar, hammer piston and tappet within the drill steel bore, the cleansing liquid flowing through the tube 28 into the drill steel bore. As the hammer piston reciprocates, pressure fluid is conducted from the forward end of the cylinder bore through the grooves in the piston striking bar and improved passage means, to be later described, in the tappetand chuck sleeve to the drill steel bore, the cleansing liquid mingling with the pressure fluid as it flows through the steel bore to the bottom of the drill hole.

The fluid distribution means for supplying pressure fluid to and exhausting fluid from the motor cylinder is of a conventional design and comprises a valve chamber 32 formed in the head member 9 and containing a reciprocable auto matic fluid distributing valve 33 herein of the sleeve type guided for reciprocatory movement on a cylindrical guide portion 34 formed integral with the head member ID and projecting within the valve chamber. The sleeve valve is formed with an enlarged circular flange 35 fitting the bore 36 of the valve chamber and having a rear pressure area 31, and a sleeve-like body portion 38 adapted to fit a bore 39 connecting the valve chamber bore with the rear end of the motor cylinder bore. Formed in the wall of the valve chamber is an annular fluid supply groove 40 to which pressure fluid is supplied through a passage 4| communicating with an annular pressure chamber 42 formed in the rear head block. Arranged in a bore 43 in the head block is a throttle valve 44 having a port 45 for conducting pressure fluid from a central supply passage 46 in the valveto a passage 41 communicating with the pressure chamber 42. This cylinder is provided with a usual piston controlled central exhaust passage 48, and a valve throwing passage 49 communicates with the cylinder bore between the rear end of the bore and the exhaust passage 48, and this passage is piston controlled and communicates with the valve chamber at the rear side of the valve for supplying throwing pressure to the rear pressure area 31 of the valve. An exhaust passage 50 connects the rear end of the valve chamber to exhaust. Formed in the valve chamber between the exhaust passage 50 and the supply groove 4|] is a groove 5| connected by a passage 52 to the forward end of the cylinder bore.

Now referring to the improved hole'blowing means associated with the fluid distribution means, it will be noted that formed in the throttle valve 44 is a port 53 having a communicating circumferential groove 54, and this groove is adapted to supply pressure fluid through a passage 55 to the valve chamber at the rear side of the valve 33. The improved passage means in the tappet and chuck sleeve for conducting pressure fluid past the tappet to the drill steel bore comprises passages 56 formed on the sides of the reduced portion of the tappet and cooperating longitudinal passages 51 cut in the walls of the chuck sleeve bore.

The operation of the rock drill motor will be clearly apparent from the description given. When the parts are in the position shown in Fig. 1 and the valve 4415 turned into a position to bring the port 45 into communication with the passage 41, pressure fluid may flow from the throttle valve through port 45, passage 41, chamber 42, passage 4|, groove 40, through the valve chamber past the valve, groove 5| and passage 52 to the front end of the cylinder bore, the pressure fluid acting on the forward pressure area of the hammer piston to drive the piston rearwardly to effect its return stroke. Upon initiation of the rearward piston movement, the rear end of the cylinder bore is connected to exhaust through the exhaust passage 48, and as the piston moves rearwardly, the piston head overruns the exhaust passage 48, thereby trapping the pressure fluid within the rear end of the cylinder, compressing the same to a relatively high pressure, and this compression pressure acts on the forward area of the valve to throw the latter rearwardly from the position shown. When the valve is in its rearward position, pressure fluid may flow from the throttle valve through port 45, passage 41, groove 42, passage 4|, groove 40 and through the axial bore 39 to the rear end of the cylinder bore, the pressure fluid acting on the rear pressure area of the piston to drive the latter forwardly to effect its working stroke, 1. e. to deliver an impact blow to the shank of the drill steel. Upon initiation of the forward piston movement the forward end of the cylinder bore is connected to exhaust through the exhaust passage 48 and the passage 52 communicating with the exhaust passage 59. As the hammer piston moves forwardly, communication of the exhaust passage 48 with the forward endof the cylinder bore is cut off by the piston head, while the passage 49 is overrun by the rear edge of the piston, thereby admitting pressure fluid from the rear end of the cylinder bore through passage 49 to the rear end of the valve chamber to act on the rear pressure area 31 of the valve to throw the valve forwardly to the position shown. Upon continued forward movement of the piston, the rear edge of the hammer piston overruns the exhaust passage 48 thereby to connect the rear end of the cylinder bore to exhaust.

When it is desired to effect a hole blowing operation, the throttle valve 44 is turned into the position shown in Fig. 1 with the port 53 communicating with the passage 41, and pressure fluid may then flow through groove 54 and passage 55 to the rear end of the valve chamber to act on the rear, pressure area 31 of the valve to hold the valve in its forward position shown in Fig. 1. Pressure fluid at the same time flows due to leakage, from the supply groove 40 through the bore 39 past the valve to the rear end of the cylinder bore. Simultaneously, pressure fluid flows from the supply groove 40 past the valve through groove 5| and passage 52 to the forward end of the cylinder bore, the pressure fluid acting on the forward pressure area of the piston to move the piston rearwardly against the opposing pressure leaking past the distributing valve through the bore 39, the hammer piston moving rearwardly until the forward edge of the piston head slightly overruns or cracks the exhaust passage 48, the pressure within the forward end of the cylinder bore then being substantially reduced by the slight leakage through the exhaust passage and the fluid flowing through the grooves 2| on the piston striking bar so that the piston is held in a substantially balanced position substantially midway between the ends of the cylinder. It will thus be seen that the fluid distributing valve 33 is at this time held by pressure fluid acting on the rear pressure area 31 in its forward position as shown in Fig. 1 so that pressure fluid flows continuously to the forward end of the cylinder bore and the hammer piston is maintained in a balanced substantially exhaust closing position within the cylinder bore, the piston being held in such position by the pressure acting on the opposed pressure areas of the piston head, thereby maintaining the exhaust passage substantially closed. Pressure fluid at this time continuously flows from the forward end of the cylinder bore through the rotation grooves 2|, past the tappet, through the passages 55, 51 and through the chuck sleeve bore to the bore 26 in the drill steel to blow out the cuttings from the drill hole. During the hole blowing operation, the drilling motor may be fed or moved rearwardly to bring the tappet away from the drill steel shank, as shown in Fig. 1, so that the pressure fluid may flow freely past the forward face of the tappet to the drill steel bore. When it is desired to shut down the motor, the throttle valve 44 is turned into its neutral position with the passage 4! cut off by the wall of the throttle valve. During normal running of the drilling motor, the tappet assumes the position shown in Fig. 2 during the return'stroke of the piston and at that time the passages 56 are cut off from the passages 51, and when the piston striking bar imparts an impact blow to the tappet, it is driven forwardly to the position shown in Fig. l to bring the passages 56 into communication with the passages 57 so that a blast of pressure fluid is conducted past the tappet to the drill steel bore at that time As a result of this invention, it will be noted that an improved hole blowing means is provided for a rock drilling motor whereby the fluid distributing valve and hammer piston are maintained in a hole blowing position in an improved and simplified manner. It will further be noted that an improved hole blowing means is provided wherein the hammer piston is maintained during the hole blowing operation in a substantially balanced position midway between the ends of the cylinder bore to cut off substantially communication of the central cylinder exhaust passage with the forward end of the cylinder so that a continuous flow of pressure fluid is effected from the forward end of the cylinder bore through the bore in the drill steel to the bottom of the drill hole to blow out the latter. It will further be evident that by the provision of the improved tappet and chuck structure, it is possibe to obtain a free flow of cleansing fluid past the tappet to the drill steel. These and other uses and advantages of the improved hole blowing means will be clearly apparent to those skille in the art.

While I have in this application specifically described one form which the invention may assume in practice, it will be understood that this form of the same is shown for purposes of illustration and that the invention may be modified and embodied in various other forms without departing from its spirit or the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent is:

1. In a rock drill, a cylinder, a hammer piston reciprocable therein, a member relative to which said piston is reciprocable for transmitting the impact blows of the hammer piston to the shank of a hollow drill steel, fluid distribution means for effecting reciprocation of said piston having an automatic fluid distributing valveand a fluid supply connection, and means operative to eflect hole blowing while fluid supply to said distributing valve takes place, and including at least a portion of said valve, for effecting a supply of pressure fluid from said supply connection to opposed pressure areas on said hammer piston, to maintain said piston in a. relatively stationary position substantially midway between the ends of said cylinder, and passage means including passages on said blow transmitting member for conducting pressure fluid from the forward end of the cylinder bore, when said hammer piston is in saidstationary position, to the hollow drill steel.

2. In a rock drill, a cylinder, a hammer piston reciprocable therein, a chuck for receiving the shank of a hollow drill steel, a member relative to which said piston is reciprocabe for transmitting the impact blows of the hammer piston to the shank of a hollow drill steel, fluid distribution means for effecting reciprocation of said piston having an automatic fluid distributing valve and a fluid supply connection, and means operative to effect hole blowing while fluid supply to said distributing valve takes place, and including at least a portion of said valve, for effecting a supply of pressure fluid from said supply connection to opposed pressure areas on said hammer piston, to maintain said piston in a relatively stationary position substantially midway between the ends of said cylinder, and passage means including passages on said blow transmitting member and in said chuck for conducting pressure fluid from the forward end of the cylinder bore, when said hammer piston is in said stationary position, to the hollow drill steel.

3. In a rock drill, in combination, a cylinder, a

piston reciprocable therein, a member relative to which said piston is reciprocable for transmitting the impact blows of the piston to the shank of a hollow drill steel, fluid distribution means for eifecting reciprocation of said piston, and means operative to effect hole blowing and including at least a portion of said fluid distribution means for effecting a supply of pressure fluid directly to the opposite ends of said cylinder to act on 0pposed pressure areas on said piston to maintain the latter in a stationary hole blowing position substantially midway between the ends of said cylinder, and passage means including passages on said blow transmitting member for conducting fluid from the forward end of the cylinder bore, when said piston is in said stationary hole blowing position, to the hollow drill steel. 4. In a rock drill, in combination, a cylinder, a piston reciprocable therein, a member relative to which said piston is reciprocable for transmitting the impact blows of the piston to the shank of a hollow drill steel, fluid distribution means for effecting reciprocation of said piston including a free cylinder exhaust port controlled by said piston, and means operative to effect hole blowing and including at least a portion of said fluid distribution means for effecting a supply of pressure fluid directly to the opposite ends of said cylinder to act on opposed pressure areas of said piston to maintain the latter in a substantially exhaust port closing position substantially midway between the ends of said cylinder, and pass age means including passages on said blow transmitting member for conducting pressure fluid from the forward end of said cylinder, when said piston is in said substantially midway position, to the hollow drill steel.

5. In a rock drill, in combination, a cylinder, a member relative to which said piston is reciprocable for transmitting the impact blows of the piston to the shank of a hollow drill steel, fluid distribution means for effecting reciprocation of said piston including an automatic fluid distributing valve, and means operative to effect hole blowing and including at least a portion of said fluid distribution means for effecting a supply of pressure fluid to a pressure area on said valve to hold the latter stationary in one position and to effect supply of pressure fluid to opposed pressure areas on said piston to maintain the latter in a stationary hole blowing posi-v tion substantially midway between the ends of said cylinder, and passage means including a passage on said blow transmitting member for conducting pressure fluid from the forward end of said cylinder, when said piston is in said stationary position, to the hollow drill steel.

6. In a rock drill, in combination, a cylinder, a piston reciprocable therein, a member relative to which said piston is reciprocable for transmitting the impact blows of said piston to the shank of a hollow drill steel, fluid distribution means for effecting reciprocation of said piston including an automatic fluid distributing valve and a cylinder exhaust port controlled by said piston, and means operative to effect hole blowing and including at least a portion of said fluid distribution means for effecting a supply of pressure fluid to a pressure area on said distributing valve to hold the latter stationary in one position and to effect a supplying of pressure fluid to opposed pressure areas on said piston to maintain the latter in a substantially exhaust port closing position substantially midway between the ends of said cylinder, and passage means including a passage on said blow transmitting member for conducting pressure fluid from the forward end of said cylinder, when said piston is in said substantially midway position, to the hollow drill steel.

'7. In a rock drill, in combination, a cylinder, a piston reciprocable therein, a member relative to which said piston is reciprocable for transmitting the impact blows of said piston to the shank of a hollow drill steel, fluid distribution means for efiecting reciprocation of said piston including an automatic fluid distributing valve, and means operative to effect hole blowing including a valve and passage means controlled by said valve for supplying pressure fluid to a pressure area on said distributing valve to hold the latter stationary in one position and to effect a supplying of pressure fluid to opposed pressure areas on said piston to maintain the latter in a stationary position substantially midway between the ends of said cylinder, and passage means including a passage on said blow transmitting member for conducting pressure fluid from the forward end of said cylinder, when said piston is in said stationary position, to the hollow drill steel.

8. In a rock drill, in combination, a cylinder, a piston reciprocable therein, a member relative to which said piston is reciprocable for transmitting the impact blows of said piston to the shank of a hollow drill steel, fluid distribution means for effecting reciprocation of said piston including an automatic fluid distributing valve, a cylinder exhaust port controlled by said piston, and means operative to effect hole blowing including a valve and passage means controlled by said Valve for supplying pressure fluid to a pressure area on said distributing valve to hold the latter stationary in one position and to effect a supplying of pressure fluid to opposed pressure areas on said piston to maintain the latter in a substantially exhaust port closing position substantially midway between the ends of said cylinder, and passage means including a passage on said blow transmitting member for conducting pressure fluid from the forward end of said cylinder, when said piston is in said substantially midway position, to the hollow drill steel.

9. In a rock drill, in combination, a cylinder, a piston reciprocable therein, a member relative to which said piston is reciprocable for transmitting the impact blows of said piston to the shank of a hollow drill steel, fluid distribution means for effecting reciprocation of said piston including an automatic fluid distributing valve, a cylinder exhaust port controlled by said piston and passages leading to the ends of the cylinder, and means operative to efiect hole blowing including a valve and passage means controlled by said valve for supplying pressure fluid to a pressure area on said distributing valve to hold the latter stationary in one position and to efiect a supplying of pressure fluid to opposed pressure areas on said piston to maintain the latter in a substantially exhaust port closing position substantially midway between the ends of said cylinder, and passage means including a passage on said blow transmitting member for conducting pressure fluid from the forward end of said cylinder, when said piston is in said substantially midway position, to the hollow drill steel, one of said fluid distributing means passages supplying pressure fluid to one pressure area on said piston, to hold the latter in said substantially midway position and the fluid flowing to the opposed pressure area on the piston to hold the same in said position, by leakage past said valve.

10. In a rock drill, in combination, a cylinder, a piston reciprocable therein, a chuck for receiving the shank of a hollow drill steel and providing a chamber, a tappet for transmitting the impact blows of the piston to the shank of said hollow drill steel, fluid distribution means for effecting reciprocation of said piston including means for supplying pressure fluid to the forward end of said cylinder, a passage on the piston for intermittently supplying pressure fluid to the chamber within said chuck, and a passage on the periphery of said tappet for conducting pressure fluid from the chuck chamber past the tappet to the hollow drill steel.

11. In a rock drill, in combination, a cylinder, apiston reciprocable therein, a chuck for receiving the shank of a hollow drill steel and providing a chamber, a tappet for transmitting the impact blows of the piston to the shank of said hollow drill steel, fluid distribution means for effecting reciprocation of said piston including means for supplying pressure fluid to the forward end of said cylinder, a passage on the piston for intermittently supplying pressure fluid to the chamber within said chuck, and a passage on said tappet for conducting pressure fluid from the chuck chamber past the tappet to the hollow drill steel, said tappet passage being automatically opened and closed upon reciprocation of said tappet.

ELMER G. GAR'IIN. 

